1. Field of the Invention
The invention relates to a charging apparatus for a vehicle and, more particularly, to a charging apparatus for a vehicle that is configured to allow charging of an automotive electric power storage device from the outside of the vehicle.
2. Description of Related Art
Electric cars and plug-in hybrid cars are configured to allow charging of the automotive batteries from the outside of the vehicles. Japanese Patent Application Publication No. 2011-015520 (JP 2011-015520 A) discloses a charging system for a vehicle. The charging system for a vehicle is configured to include a vehicle on which a battery is mounted, an external electric power supply, and a charging cable that connects the external electric power supply and the vehicle to each other. The vehicle includes a charging port (charging inlet), a main battery, an auxiliary battery, and a charger that is disposed between the main battery and the charging port.
In the charger, AC electric power that is provided from the outside of the vehicle is converted into DC electric power by an AC-DC converter. The DC electric power is smoothed by a capacitor. According to the technique that is disclosed in JP 2011-015520 A, the electric power that is supplied from the outside is stable to the point of allowing the smoothing by the capacitor.
However, the AC electric power that is provided from the outside of the vehicle may be of various types. For example, the input electric power supply voltage and the electric power supply frequency may vary in the case of electric power from power generators which are placed outdoors and electric power from commercial electric power supplies in countries with unstable electric power supply and the like. When the electric power supply voltage drops or the electric power supply frequency is lowered, the voltage of the capacitor that is DC-converted may drop and charging by the charger stop. When the charger stops charging, the vehicle may not be able to travel a scheduled distance. In addition, the electric power storage device of the vehicle may be used as an emergency electric power supply in some cases. In order to prepare for these cases, it is preferable that the electric power storage device is charged with as much electric power as possible.